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Discussion Starter · #1 ·
So I am approaching the end of the remodel of a basement space in to a nice little 18'x12' home theater featuring a nice compliment of Definitive Technology speakers and subwoofers duties by a couple of passive SVS subwoofers. During the course of the process I expanded from a 5.1 system to a 7.1 system. I had everything hooked up and ready to go and the HDMI from the Blu-ray was not passing through my receiver, an Onkyo SR805. HDMI to the projector would run just fine. Tried numerous HDMI cables, resetting receiver and Blu-ray player and still no signal would pass to my receiver. More than likely I have suffered the fate of others where this generation of Onkyo receivers has a high likelihood of HDMI board failure. Not the way I wanted to fire up my home theater rig after the work that I put into the room.

So now I am left trying to drive a 7.1 system through the optical output of my Blu-ray player. So here are my questions:

-What are the best surround formats to choose from to utilize the 7.1 set-up through optical?

-How much fidelity am I missing out on by not utilizing the lossless sound formats?

-Should I run bitstream or PCM to the receiver?

I appreciate any help that you can offer me in buying some time until I can upgrade to some Emotiva separates.
 

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As there's no native 7.1 over optical, apply PLIIx or DTS Neo:6 to expand 5.1 to 7.1. I'd recommend PLIIx as it produces stereo rears while Neo:6 does a mono rear channel fed to both speakers.


No, you are not missing much without lossless. The high bitrate lossy outputs on Blu-ray sound great, rivaling lossless in quality.


With optical, you must use bitstream as PCM is limited to stereo.
 

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You should experiment and choose the 5.1 -> 7.1 expansion you like best, but as an 805 owner myself I'll share the results of a couple of experiments I've run in the past.


A few years ago, I did an experiment on DPL IIx/DTS: Neo/THX Cinema using Soho54's audio test DVD, which has audio encoded individually for each channel (L/C/R/LS/RS). I sent either right surround or left surround audio to the decoder with the L/C/R/LS/RS speakers disengaged so that only the back surround channels were active. My tests was essentially worst case for a matirx expansion algorithm since there was no other channel information for the decoder to derive it's steering cues from. THX Cinema routed a majority of the sound to the back channel that corresponded to the side channel being input (RS -> RBS / LS->LBS) with only a very little bleed into the other back channel. DPL IIx and DTS: Neo produced a mono output feeding both back surrounds equally and at a reduced level when referenced to the THX output. I would assume this more aggressive steering logic continues with normal signal sources. Whether you prefer it could be a different matter.


With the 805, choosing a THX mode also alters the Audyssey target curve being used. The standard Audyssey curve has a high frequency rolloff starting around 10KHz that rolls off to about -6dB at 20kHz, IIRC. When you use a THX mode, the 805 switches to the Audyssey "flat" curve, which has no rolloff. This is to prevent having the Audyssey rolloff being applied on top of the rolloff from Re-EQ. After a bit of experimenting, I choose to set Re-EQ=Off and use the THX modes to get the flattest in room frequency response possible. You have to disable Re-EQ after each power cycle...I set it as part of my Harmony's power-on sequence. Again, your taste my vary.


-Brent
 

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Oops. I also wanted to second BI's endorsement of the lossy codecs. A couple of reviewers from HEMagazine, an e-zine that appears to have disappeared, spent time at both Dolby and DTS' labs. Dolby has a rather sophisticated setup for doing blind A/B comparisons. One of the reviewers admitted he couldn't determine any difference at all between DD and TrueHD audio tracks. The other reviewer claimed he could *occasionally* detect differences, but I can't remember if the article actually included his right/wrong ratio. DTS' lab wasn't set up for blind A/B testing, but the reviewers reported a similar experience with DTS vs. DTS-HD MA.


When trying to compare codecs at home using a disc, it gets harder. In the HEMag tests, the lossy and lossless tracks were encoded from the same master track. According to that article and others I've read, there's no guarantee that the lossy and lossless tracks on a disc that contains both actually came from the same master mix.


IMHO, the biggest advantage of the lossless codecs is the abilty to do 7.1 (or more) discrete where lossy is limited to 5.1. Technically, I think DTS squeezed in a 6.1 discrete lossy format at some point, but I don't think it's been widely used. The second biggest advantage is probably the placebo effect of the word "lossless". ;-)


-Brent
 

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Discussion Starter · #5 ·
It really comes down to every time I go to crank up the system and I hear something I don't like I start leaning on the fact that I do not have the lossless format. I will have to start experimenting with different formats to find which one I like along with the THX options enabled/disabled. I really appreciate the efforts to steer me in the right direction.
 
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